Metamagnetism in EnPdIn and EuAuIn

EuPdIn and EuAuIn were prepared by reaction of the elemental components in tantalum tubes. They crystallize with the TiNiSi structure in space group Pnma and with Z=4 formula units per unit cell. Both structures were refined from single-crystal X-ray data: a=748.30(13) pm, b=447.20(8) pm, c=853.50(14) pm, V=0.28562(5) nm(3), wR2=0.0408, 449 F-2 values, 20 variables for EuPdIn; and a=755.2(2) pm, b=472.2(1) pm, c=842.3(2) pm, V=0.3004(2) nm(3), wR2=0.0470, 524 F-2 values, 20 variables for EuAuIn. Magnetic susceptibility measurements show Curie-Weiss behaviour above 40 K for both compounds with experimental magnetic moments of 7.6(1) mu(B)/Eu (EuPdIn) and 7.5(1) mu(B)/Eu (EuAuIn), which are close to that of the free Eu2+ ion, namely mu(eff)=7.94 mu(B)/Eu. At an external field strength of 0.01 T, EuPdIn and EuAuIn order antiferromagnetically at 13.0(5) and 21.0(5) K, respectively. Magnetization measurements at 5 K indicate metamagnetism with a magnetic moment of 5.9(1) mu(B)/Eu at 5.5 T for both compounds. The critical fields amount to 3.1(1) T for EuPdIn and 0.25(2) T for EuAuIn. Both compounds are good metallic conductors with specific resistivities of 23 (EuPdIn) and 96 mu Omega cm (EuAuIn) at room temperature.